diff options
Diffstat (limited to 'login')
| -rw-r--r-- | login/utmp_file.c | 80 |
1 files changed, 28 insertions, 52 deletions
diff --git a/login/utmp_file.c b/login/utmp_file.c index 5e4e66d1d0..f3c528384f 100644 --- a/login/utmp_file.c +++ b/login/utmp_file.c @@ -55,32 +55,23 @@ static void timeout_handler (int signum) {}; /* try_file_lock (LOCKING, FD, TYPE) returns true if the locking operation failed and recovery needs to be performed. - (file_lock_restore (LOCKING) still needs to be called.) file_unlock (FD) removes the lock (which must have been - acquired). - - file_lock_restore (LOCKING) is needed to clean up in both - cases. */ - -struct file_locking -{ - struct sigaction old_action; - unsigned int old_timeout; -}; + successfully acquired). */ static bool -try_file_lock (struct file_locking *locking, int fd, int type) +try_file_lock (int fd, int type) { /* Cancel any existing alarm. */ - locking->old_timeout = alarm (0); + int old_timeout = alarm (0); /* Establish signal handler. */ + struct sigaction old_action; struct sigaction action; action.sa_handler = timeout_handler; __sigemptyset (&action.sa_mask); action.sa_flags = 0; - __sigaction (SIGALRM, &action, &locking->old_action); + __sigaction (SIGALRM, &action, &old_action); alarm (TIMEOUT); @@ -90,7 +81,23 @@ try_file_lock (struct file_locking *locking, int fd, int type) .l_type = type, fl.l_whence = SEEK_SET, }; - return __fcntl64_nocancel (fd, F_SETLKW, &fl) < 0; + + bool status = __fcntl64_nocancel (fd, F_SETLKW, &fl) < 0; + int saved_errno = errno; + + /* Reset the signal handler and alarm. We must reset the alarm + before resetting the handler so our alarm does not generate a + spurious SIGALRM seen by the user. However, we cannot just set + the user's old alarm before restoring the handler, because then + it's possible our handler could catch the user alarm's SIGARLM and + then the user would never see the signal he expected. */ + alarm (0); + __sigaction (SIGALRM, &old_action, NULL); + if (old_timeout != 0) + alarm (old_timeout); + + __set_errno (saved_errno); + return status; } static void @@ -103,21 +110,6 @@ file_unlock (int fd) __fcntl64_nocancel (fd, F_SETLKW, &fl); } -static void -file_lock_restore (struct file_locking *locking) -{ - /* Reset the signal handler and alarm. We must reset the alarm - before resetting the handler so our alarm does not generate a - spurious SIGALRM seen by the user. However, we cannot just set - the user's old alarm before restoring the handler, because then - it's possible our handler could catch the user alarm's SIGARLM - and then the user would never see the signal he expected. */ - alarm (0); - __sigaction (SIGALRM, &locking->old_action, NULL); - if (locking->old_timeout != 0) - alarm (locking->old_timeout); -} - #ifndef TRANSFORM_UTMP_FILE_NAME # define TRANSFORM_UTMP_FILE_NAME(file_name) (file_name) #endif @@ -166,8 +158,7 @@ __libc_getutent_r (struct utmp *buffer, struct utmp **result) return -1; } - struct file_locking fl; - if (try_file_lock (&fl, file_fd, F_RDLCK)) + if (try_file_lock (file_fd, F_RDLCK)) nbytes = 0; else { @@ -175,7 +166,6 @@ __libc_getutent_r (struct utmp *buffer, struct utmp **result) nbytes = __read_nocancel (file_fd, &last_entry, sizeof (struct utmp)); file_unlock (file_fd); } - file_lock_restore (&fl); if (nbytes != sizeof (struct utmp)) { @@ -201,11 +191,9 @@ internal_getut_r (const struct utmp *id, struct utmp *buffer, { int result = -1; - struct file_locking fl; - if (try_file_lock (&fl, file_fd, F_RDLCK)) + if (try_file_lock (file_fd, F_RDLCK)) { *lock_failed = true; - file_lock_restore (&fl); return -1; } @@ -257,7 +245,6 @@ internal_getut_r (const struct utmp *id, struct utmp *buffer, unlock_return: file_unlock (file_fd); - file_lock_restore (&fl); return result; } @@ -303,11 +290,9 @@ __libc_getutline_r (const struct utmp *line, struct utmp *buffer, return -1; } - struct file_locking fl; - if (try_file_lock (&fl, file_fd, F_RDLCK)) + if (try_file_lock (file_fd, F_RDLCK)) { *result = NULL; - file_lock_restore (&fl); return -1; } @@ -337,7 +322,6 @@ __libc_getutline_r (const struct utmp *line, struct utmp *buffer, unlock_return: file_unlock (file_fd); - file_lock_restore (&fl); return ((*result == NULL) ? -1 : 0); } @@ -394,12 +378,8 @@ __libc_pututline (const struct utmp *data) } } - struct file_locking fl; - if (try_file_lock (&fl, file_fd, F_WRLCK)) - { - file_lock_restore (&fl); - return NULL; - } + if (try_file_lock (file_fd, F_WRLCK)) + return NULL; if (found < 0) { @@ -442,7 +422,6 @@ __libc_pututline (const struct utmp *data) unlock_return: file_unlock (file_fd); - file_lock_restore (&fl); return pbuf; } @@ -471,10 +450,8 @@ __libc_updwtmp (const char *file, const struct utmp *utmp) if (fd < 0) return -1; - struct file_locking fl; - if (try_file_lock (&fl, fd, F_WRLCK)) + if (try_file_lock (fd, F_WRLCK)) { - file_lock_restore (&fl); __close_nocancel_nostatus (fd); return -1; } @@ -504,7 +481,6 @@ __libc_updwtmp (const char *file, const struct utmp *utmp) unlock_return: file_unlock (fd); - file_lock_restore (&fl); /* Close WTMP file. */ __close_nocancel_nostatus (fd); |